Panel illumination



April 28, 1964 J. w. FELDMAYER PANEL ILLUMINATION Filed March 28, 1962 I I x i I l I INVENTOR. JOHN W. FELDMAYER W ATTORNEY United States Patent 3,130,511 PANEL HJLUMENATIDN John W. Feldmayer, Levittown, Pa., assignor to the United States of America as represented by the Secretary of the Navy Filed Mar. 28, 1962, Ser. No. 183,313 7 Claims. (Cl. 40-130) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to illuminated display panels and more particularly to edge-illuminated instrument panels utilizing a plurality of light colors for positively distinguishing various indicia and dials thereon from each other.

So-called edge-illumination in which the light source is positioned at the edge of a transparent plate has proved to be extremely useful in aircraft instrument panels es pecially during nighttime missions because it efficiently confines the light energy to the indicia and dial display contained thereon. In some aircraft instrument panels, rapid orientation of the pilots eyes to a crowded and congested display is enhanced by color-coding the several instrument indicia and dials. This has become increasingly important in high performance aircraft on complex tactical missions where very complex, integrated navigational display panels are used.

One prior art method of color-coding is to provide separate color filters at each panel display element. Another utilizes plural light sources at different edge positions in the panel each radiating a different color into the panel. The first method is usually expensive; and the second method produces blending of the difierent colors in large overlapping areas which render the colors indiscernible to the eye. Color blending is particularly prevalent in small panels requiring many different colors of illumination.

Accordingly, it is an object of the present invention to provide a novel edge-illuminated instrument panel having color-coded lighting of the various indicia displayed thereon, with which a single light source radiates a plurality of illuminating colors into the panel, with which there is no blending of the several illuminating colors regardless of the size of the instrument panel and close proximity of the display elements, and with which the instrument panel is of unitary construction.

Another object of the invention is to provide an improved means for the eflicient transmission of edge-illuminated light to various displayed indicia and legends on dials and controls which are affixed to and form a part of an instrument panel.

Still another object of the invention is to provide an improved method and apparatus for the illumination of instrument panels which will be relatively simple, convenient, practical, and inexpensive.

Various other objects and advantages will be apparent from the following description of one embodiment of the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

FIG. 1 represents a front view of an instrument display panel embodying the present invention;

FIG. 2 represents a fragmentary cross-sectional view of the instrument display panel taken through the light source along the line 22 of FIG. 1;

FIG. 3 represents a cross-sectional view of the light source taken along the line 33 of FIG. 2;

FIG. 4 represents a fragmentary cross-sectional view of the instrument panel taken through the two control dials along the line 44 of FIG. 1; and

FIG. 5 represents another fragmentary cross-sectional view of the instrument panel taken through the indicator along the line-55 of FIG. 1.

A typical instrument display panel, indicated generally by the numeral 10, includes two control dials 11 and 12, and an indicator 13. Of course these elements are illustrative only and may be conveniently positioned relative to each other in order to satisfy particular requirements or specifications. As best illustrated in FIG. 4, the panel 10 is composed of a clear transparent plastic or glass plate 14 or such other light-conducting rigid material and is completely coated on both sides and around the edges with two laminated layers 16 and 17 of coating material such as a vinyl plastic. The inner layer 16 must be a translucent plastic so that the outer surface is illuminated and glows when any light is transmitted therethrough. The outer layer 17 must be of an opaque plastic to prevent light transmission and removable from the inner layer 16 as desired to produce legends and indicia. The outer layer 17 may be of various colors, but black is preferred in most applications so as not to reflect light and to pro vide a contrasting background for the illuminating legends and indicia. The translucent inner layer 16 should transmit the whole color spectrum so that any selected color illumination will not be attenuated.

The panel 14 is edge-illuminated from a single light source, indicated generally by the numeral 18, and radiates a plurality of colors therefrom in a manner now to be described. An aperture 22 formed in the panel 10 contains an incandescent bulb 19 which is held in position and electrically energized by means of an electrical receptacle 21 secured to the panel 10. The position of the aperture 22 is such that it will provide unobstructed light transmittance through the plate 14 to regions of the panel 19 where the control dials 11 and 12 and the indicator 13 are located. The receptacle 21 is held in the secured position by a cap 23 screwed onto the insertion end of the receptacle 21 from the front side of the panel 10. In the illustrated embodiment, the aperture 22 is lined with three transparent, color-filter segments 26, 27 and 28 which completely encircle the bulb 19. Each segment thereby radiates a colored light into the transparent plate 14 in accordance with the particular color-filter selected. For purposes of this illustration, segments 26, 27 and 28 are hereinafter identified as red, green and yellow.

To prevent the three different illuminating colors from blending within the transparent plate 14 particularly at the control dials 11 and 12 and the indicator 13, radial grooves 31, 32 and 33 are formed in the panel 10 from the rear side through the outer and inner layers 17 and 16 and the transparent plate 14 up to but not through the translucent inner layer 16 on the front of the panel 10. The grooves 31, 32 and 33 so formed are radial with respect to the bulb 19 and coincide with the small radial spacings formed between adjacent segments. The grooves are each filled with an opaque bonding filler 34 to prevent light from transmitting into adjacent portions of the sep arated plate 14, and to maintain a rigid panel construction. Thus, the panel region bounded by the periphery of the panel 10 and the grooves 31 and 32 will transmit only the color of light radiating through the segment 26, namely, red. Similarly, the areas bounded by the grooves 32 and 33 and the grooves 31 and 33 will be restricted to transmitting'green and yellow illumination, respectively.

Three modes of transmittance and illumination are contemplated for use in the invention. The first mode is embodied in the control dial 11 which comprises a transparent disk 36 of the same thickness as the plate 14, similarly coated with inner and outer laminated layers 16' and 17' on the front and back, and coplanar with the panel 10. The disk 36 is coaxially fixed on a shaft 37 and rotatable therewith for operating control elements not shown. A portion of the outer layer 17 on the dial 11 is removed so as to expose the inner length 16 as the desired indicia, such as a pointer 38. The red light radiating from the light source 18 through the plate 14 is transmitted into the disk 36 and is reflected in the translucent inner layer 16' thereby producing a visible red indicia at the pointer 58. Graduations 39 are similarly formed on the panel 10.

The second mode of transmittance and illumination is embodied in the control dial 12 which comprises a trans parent disk 40 coaxially supported on a shaft 41 and r tatable therewith. The disk 49 is also coated on the front side with inner and outer laminated layers 16" and 17 similar to layers 16 and 17. No coating is placed on the rear side of the disk 40 which is adjacent to the front of the panel 10, and the outer layer 17 on the plate 14 which is behind the disk 40 is removed to permit light transmittance into the disk 40. A marking, such as a pointer 42 is formed on the disk 39 by removing a portion of outer layer 17" and graduations 43 are similarly formed on the front surface of the panel 10. The green light radiating from the light source 18 through the plate 14 is transmitted into the disk 40 and is reflected in the translucent inner layer 16" thereby producing a visible green indicia at the pointer 42.

The third mode of illumination is embodied in the indicator 13 wherein an aperture 46 is cut through the panel with a beveled edge facing rearwardly. The yellow light transmitted from the light source 18 through the transparent plate 14 of the panel 10 is refracted therefrom toward an indicator scale 47 mounted behind the aperture 46.

7 It should now be apparent, that the present invention affords a simple and inexpensive edge-illuminated instrument panel in which various modes of transmittance and illumination are possible, and in which the several panel indicators or elements can be illuminated in distanct colors from a single light source without any undesirable blending or dispersion of the colors to cause confusion to the viewer. It will also be apparent that the use of small display panels in limited spaces, such as found in aircraft, are enhanced since only a single light source is contemplated.

It will be understood that various changes in the details, materials, steps and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

What is claimed is:

1. An edge-illuminated instrument panel comprising: a rigid transparent plate adapted to be mounted in a control panel, a translucent layer fixed to and completely enveloping both sides and the peripheral edge of said plate, an opaque layer fixed to and completely covering said translucent layer as fixed on said plate, said opaque layer being interrupted at preselected areas to expose said translucent layer and to define indicia when light escapes from said plate through the interrupted areas of said opaque layer, an aperture formed in said plate, a light source juxtapositioned within said aperture for edgeilluminating said plate, a plurality of transparent segments forming an annular lining at the edge of said plate within said aperture and encircling said light source, said segments having preselected color-transmitting characteristics, a plurality of grooves each emanating from the abutting ends of said segments formed in said plate through said opaque and translucent layers on one side thereof and up to the inner face of said translucent layer on the opposite side of said plate, and an opaque bonding material filling said grooves; whereby the several illuminating colors from said segments cannot blend in said plate.

[i 2. An edge-illuminated instrument panel comprising: a rigid transparent plate adapted to be mounted in a control panel, a translucent layer fixed to and completely enveloping both sides of said plate, an opaque layer fixed to and completely covering said translucent layer as fixed on said plate, said opaque layer being interrupted at preselected areas to expose said translucent layer and to define indicia when light escapes from said plate through the interrupted areas of said opaque layer, a light source juxtapositioned within the plane of said plate for edgeillumination thereof, an annular element at the edge of said plate encircling said light source, said element having a plurality of color-transmitting characteristics, a plurality of grooves each emanating at the color delineations of said element formed in said plate through said opaque and translucent layers on one side thereof and up to the inner face of said translucent layer on the opposite side of said plate, and an opaque bonding material filling said grooves; whereby the several illuminating colors from said element cannot blend in said plate.

3. An edge-illuminated instrument panel comprising: a rigid transparent plate adapted to be mounted in a control panel, a translucent layer fixed to and completely enveloping both sides and the peripheral edge of said plate, an opaque layer fixed to and completely covering said translucent layer as formed on said plate, said opaque layer being interrupted at preselected areas to expose said translucent layer and to define indicia when light escapes from said plate through the interrupted areas of said opaque layer, a plurality of apertures formed in said plate, a light source juxtapositioned within one of said apertures for edge-illuminating said plate, a plurality of transparent segments forming an annular lining at the edge of said plate within said one aperture and encircling said light source, said segments having preselected colortransmitting characteristics, a plurality of grooves each emanating from the abutting ends of said segments formed in said plate through said opaque and translucent layers on one side thereof and up to the inner face of said translucent layer on the opposite side of said plate, an opaque its front surface and periphery with translucent and opaque layers, said opaque layer on said plate adjacent to said disk being interrupted to radiate light from said plate into said disk and said opaque layer on said first and second dials being interrupted to define indicia when light escapes from said plate through the interrupted areas.

4. An edge-illuminated instrument panel comprising:

a rigid transparent plate adapted to be mounted in a con- 7 trol panel, an inner translucent layer and an outer opaque layer fixed to and completely enveloping both sides and the peripheral edge of said plate, said opaque layer being interrupted at preselected areas to expose said translucent layer and to define indicia when light escapes fiom said plate through the interrupted areas of said opaque layer, an aperture and a light source juxtapositioned within said aperture in said plate for edge-illumination thereof, an annular element at the edge of said plate within the aperture and enveloping said light source, and having a plurality of color-transmitting characteristics, a groove emanating at the color delineations of said element formed in said plate through said opaque and translucent layers on one side thereof and said transparent plate up to the translucent layer on the opposite side of said plate, an opaque bonding material filling said grooves, and dial means mounted on said plate for producing indicia therea on from light escaping from said plate.

5. The instrument panel of claim 4 having another aperture formed in said plate wherein said dial means is selectively juxtapositioned therewithin, said dial means including a rigid transparent disk coplanar with said plate and coated on both sides with translucent and opaque layers, said opaque layer on said disk being interrupted to define indicia when the light is transmitted from said plate through the interrupted areas.

6. The instrument panel of claim 4 having another aperture formed in said plate wherein said dial means is selectively juxtapositioned therewithin, said dial means including a rigid transparent disk adjacent to the front side of said plate and coated on its front surface and periphery with translucent and opaque layers, said opaque layer on said plate adjacent to said disk being interrupted to radiate light from said plate into said disk and said opaque layer on said disk being interrupted to define indicia when the light is transmitted from said plate through the interrupted areas.

7. The instrument panel of claim 4 having apertures formed in said plate wherein said dial means includes a first and second dial means selectively juxtapositioned therewithin, said first dial means including a rigid transparent disk coplanar with said plate and coated on both sides with translucent and opaque layers, said second dial including a rigid transparent disk adjacent to the front side of said plate and coated on its front surface and periphery with translucent and opaque layers, said opaque layer on said plate adjacent to said disk being interrupted to radiate light from said plate into said disk and said opaque layer on said first and second dial means being interrupted to define indicia when the light is transmitted from said plate through the interrupted areas.

References Cited in the file of this patent UNITED STATES PATENTS 2,507,035 Maynard May 9, 1950 2,682,251 Neugass June 29, 1954 2,731,960 Neugass Jan. 24, 1956 2,740,957 Davies Apr. 3, 1956 2,755,687 Cushrnan Dec. 25, 1956 2,831,453 Hardesty Apr. 22, 1958 2,880,536 Sullivan Apr. 7, 1959 2,945,313 Hardesty July 19, 1960 2,948,073 Roper Aug. 9, 1960 2,998,597 Edwards Aug. 29, 1961 

2. AN EDGE-ILLUMINATED INSTRUMENT PANEL COMPRISING: A RIGID TRANSPARENT PLATE ADAPTED TO BE MOUNTED IN A CONTROL PANEL, A TRANSLUCENT LAYER FIXED TO AND COMPLETELY ENVELOPING BOTH SIDES OF SAID PLATE, AN OPAQUE LAYER FIXED TO AND COMPLETELY COVERING SAID TRANSLUCENT LAYER AS FIXED ON SAID PLATE, SAID OPAQUE LAYER BEING INTERRUPTED AT PRESELECTED AREAS TO EXPOSE SAID TRANSLUCENT LAYER AND TO DEFINE INDICIA WHEN LIGHT ESCAPES FROM SAID PLATE THROUGH THE INTERRUPTED AREAS OF SAID OPAQUE LAYER, A LIGHT SOURCE JUXTAPOSITIONED WITHIN THE PLANE OF SAID PLATE FOR EDGEILLUMINATION THEREOF, AN ANNULAR ELEMENT AT THE EDGE OF SAID PLATE ENCIRCLING SAID LIGHT SOURCE, SAID ELEMENT HAVING A PLURALITY OF COLOR-TRANSMITTING CHARACTERISTICS, A PLURALITY OF GROOVES EACH EMANATING AT THE COLOR DELINEATIONS OF SAID ELEMENT FORMED IN SAID PLATE THROUGH SAID OPAQUE AND TRANSLUCENT LAYERS ON ONE SIDE THEREOF AND UP TO THE INNER FACE OF SAID TRANSLUCENT LAYER ON THE OPPOSITE SIDE OF SAID PLATE, AND AN OPAQUE BONDING MATERIAL FILLING SAID GROOVES; WHEREBY THE SEVERAL ILLUMINATING COLORS FROM SAID ELEMENT CANNOT BLEND IN SAID PLATE. 